Mycelium and mycelium-biomass composites are emerging as new sustainable materials with useful flame-retardant potentials. Here we report a detailed characterisation of the thermal degradation and fire properties of fungal mycelium and mycelium-biomass composites. Measurements and analyses are carried out on key parameters such as decomposition temperatures, residual char, and gases evolved during pyrolysis. Pyrolysis flow combustion calorimetry (PCFC) evaluations reveal that the corresponding combustion propensity of mycelium is significantly lower compared to poly(methyl methacrylate) (PMMA) and polylactic acid (PLA), indicating that they are noticeably less prone to ignition and flaming combustion, and therefore safer to use. The hyphal diameters of mycelium decrease following pyrolysis. Cone calorimetry testing results show that the presence of mycelium has a positive influence on the fire reaction properties of wheat grains. This improvement is attributable to the relatively higher charring tendency of mycelium compared to wheat grain, which reduces the heat release rate (HRR) by acting as a thermal insulator and by limiting the supply of combustible gases to the flame front. The mycelium growth time has been found to yield no significant improvements in the fire properties of mycelium-wheat grain composites.

Summary Mycelial growth attracts academic and commercial interest because of its ability to upcycle agricultural and industrial wastes into economical and environmentally sustainable composite materials using a natural, low‐energy manufacturing process able to sequester carbon. This study aims to characterise the effect of varying ratios of high silica agricultural and industrial wastes on the flammability of mycelium composites, relative to typical synthetic construction materials. The results reveal that mycelium composites are safer than the traditional construction materials considered, producing much lower average and peak heat release rates and longer time to flashover. They also release significantly less smoke and CO2, although CO production fluctuated. Rice hulls yielded significant char and silica ash which improved fire performance, but composites containing glass fines exhibited the best fire performance because of their significantly higher silica concentrations and low combustible material content. Higher concentrations of glass fines increased volume‐specific cost but reduced mass‐specific and density‐specific costs. The findings of this study show that mycelium composites are a very economical alternative to highly flammable petroleum‐derived and natural gas‐derived synthetic polymers and engineered woods for applications including insulation, furniture, and panelling.

a b s t r a c tBasalt fibres are emerging as a replacement to E-glass fibres in polymer matrix composites for selected applications. In this study, the fire structural resistance of a basalt fibre composite is determined experimentally and analytically, and it is compared against an equivalent laminate reinforced with E-glass fibres. When exposed to the same radiant heat flux, the basalt fibre composite heated up more rapidly and reached higher temperatures than the glass fibre laminate due to its higher thermal emissivity. The tensile structural survivability of the basalt fibre composite was inferior to the glass fibre laminate when exposed to the same radiant heat flux. Tensile softening of both materials occurred by thermal softening and decomposition of the polymer matrix and weakening of the fibre reinforcement, which occur at similar rates. The inferior fire resistance of the basalt fibre composite is due mainly to higher emissivity, which causes it to become hotter in fire.

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Summary The structural performance of polymer composites reinforced with plant fibres when exposed to fire was experimentally evaluated and compared against an E‐glass fibre laminate. Fire testing under combined one‐sided radiant heating and static tensile loading revealed that flax, jute, or hemp fibre composites experience more rapid thermal softening and fail within much shorter times than the fibreglass laminate, which is indicative of vastly inferior structural performance in fire. The plant fibre composites soften and fail before the onset of thermal decomposition of the plant fibres and polymer matrix, whereas the E‐glass fibres provide the composite with superior tensile properties to higher temperatures and higher applied tensile stresses. The tensile performance of the three types of plant fibre composites in fire was not identical. When exposed to the same radiant heat flux, the flax fibre composite could withstand higher tensile stresses for longer times than the hemp and jute laminates, which showed similar performance.

The energy efficiency of buildings drives the replacement of traditional construction materials with lightweight insulating materials. However, energy-efficient but combustible insulation might contribute to the building’s fire load. Therefore, it is necessary to analyse the reaction-to-fire properties of various insulating materials to provide a better understanding of designing a fire-safe structure. In this study, reaction-to-fire tests were carried out to assess the fire behaviour of lightweight polystyrene insulating panels commonly employed in high-rise buildings. The flammability characteristics of expanded polystyrene (EPS) and extruded polystyrene (XPS) were determined using a cone calorimeter under two distinct external irradiance regimes, 35 kW/m2 and 50 kW/m2, to approximate small to medium fire exposure situations. To investigate the effect of a fire-rated (FR) foil layer on a sandwich panel, three distinct test configurations were used: (i) sample without FR layer (standard sample), (ii) sample with FR layer (FR foil), and (iii) damaged layer (foil and vent) for EPS. Except for the smoke toxicity index (STI), the overall fire performance of EPS is superior to that of XPS. The findings of this study are useful in analysing fire performance and fire safety design for lightweight insulation panels.